Shaped mold and a method of using same to assemble sandwich of a sheet of flexible interlayer material with bent glass sheets

ABSTRACT

A mold for supporting a flexible sheet of interlayer material for assembly against a bent glass sheet or between a pair of bent glass sheets of matching configuration has a first apertured wall shaped to conform to the shape of the bent glass, and a second apertured wall of conforming shape adapted for coupling to a vacuum source to form and hold the flexible sheet of interlayer material against the mold in unwrinkled condition. The mold is pivoted to a carriage from a mold loading orientation of convex elevational configuration to a mold unloading orientation of concave elevational configuration. Carriage movement between a mold loading station and an assembly station is correlated to the elevational configuration of the mold in a method of using the mold in assembling said flexible sheet of interlayer material againt one or more bent glass sheets.

RELATION TO OTHER APPLICATIONS

The present application is one of several related copending applicationsthat involve inventions incorporated in a method and apparatus forassembling sandwiches comprising a flexible sheet of interlayer materialand a pair of bent glass sheets while the latter retain at least aportion of residual heat from their shaping. These applications include:

(1) U.S. patent application Ser. No. 287,595 of James L. Valimont forMETHOD AND APPARATUS FOR ASSEMBLING SANDWICHES COMPRISING HOT BENT GLASSSHEETS filed July 28, 1981;

(2) U.S. patent application Ser. No. 287,600, of James L. Valimont andJoseph D. Kelly for ARRANGEMENT OF VACUUM CUPS TO ASSEMBLE ONE OR MOREBENT GLASS SHEETS WITH A SHEET OF FLEXIBLE INTERLAYER MATERIAL filedJuly 28, 1981;

(3) U.S. patent application Ser. No. 287,607 of James L. Valimont andHershel L. Phares, for SHAPED MOLD AND A METHOD OF USING SAME TOASSEMBLE SANDWICH OF A SHEET OF FLEXIBLE INTERLAYER MATERIAL WITH BENTGLASS SHEETS filed July 28, 1981 (the present invention);

(4) U.S. patent application Ser. No. 287,608 of James L. Valimont andBarry L. Shadle for ALIGNING BENT GLASS SHEETS FOR ASSEMBLY INTO BENTGLASS SHEET SANDWICHES filed July 28, 1981.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the assembly of sheets to be fabricatedinto bent laminated windshields. Conventionally, bent laminatedwindshields for automobiles are fabricated using several separate steps.The first step involves bending a doublet, or a pair of glass sheets,into shapes that conform to the shape desired for the bent laminatedwindshield. The two sheets are bent as a pair so that their shapeconforms to one another throughout the entire extent of the glasssheets. A tunnel-like lehr is used to heat the pair of bent glass sheetsin unison to conform to the upwardly facing shaping surface of a bendingmold.

Usually a parting material is applied to facilitate separating thesheets after the bending operation is completed. A particularly goodtechnique for supplying the parting material involves spraying anaqueous suspension of fine diatomaceous earth in the manner disclosed inU.S. Pat. No. 2,725,320 to Atkeson and Golightly. The benefit of thispatented process is that it is unnecessary to wash the parting materialfrom between the interfacial surfaces of the matching bent glass sheetswhen the bent glass sheets are separated prior to assembling the sheetswith a flexible sheet of interlayer material to form a sandwich.

A second step, which conventionally has taken place in an area remotefrom the glass bending lehr, involves the assembly of the pair ofmatched bent glass sheets with a flexible sheet of plasticizedinterlayer material to form the sandwich to be laminated. An interlayerfor laminated safety glass windshields for automobiles presently usedcommercially is composed of a plasticized polyvinyl acetal resin,preferably polyvinyl butyral prepared in the manner recited in U.S. Pat.No. 2,400,957 to Stamatoff.

The polyvinyl butyrals contain a plasticizer. Generally, the plasticizerused is a water-insoluble ester of a polybasic acid and a polyhydricalcohol. Particularly desirable plasticizers for use with theinterlayers assembled between pairs of bent glass sheets of matchingcurvature are triethylene glycol di(2-ethyl butyrate), dibutyl sebacate,di(beta-butoxyethyl) sebacate, dioctyl phthalate, and di-n-hexyladipate.

Other interlayer materials include certain polyurethanes, preferablythose derived by reacting an organic polyisocyanate with a materialhaving a multiplicity of active hydrogen sites, such as a polyetherpolyol and/or a polyester polyol or a polyamine. U.S. Pat. No. 3,808,077to Rieser and Chabal discloses polyurethanes suitable for use as theinner layer of bilayer windshields, which comprise an outer glass sheetand an inner layer of polyurethane. These polyurethane compositions arealso useful as interlayers in conventional windshields of two glasssheets and an interlayer.

After the sandwich is assembled, it is laminated. In the manufacture oflaminated windshields comprising a pair of matched sheets of bent glassand a thermoplastic interlayer, it is desirable to obtain a completeadhesive bond between the glass sheets and the thermoplastic interlayer.This complete adhesive bond is obtained commercially by subjecting theassembled glass and plastic sheets to heat and pressure while immersedin a hot oil bath while within an autoclave. Unless the marginal edgesof the laminated assemblies are sealed by bonding the glass to thethermoplastic interlayer before the assembly is exposed to the oil bath,the oil in the autoclave may penetrate between the two sheets of glassand the interlayer. The assembly being laminated is discolored in theportion where oil penetration takes place.

In preparing assemblies for the autoclave, two bent glass sheets and aplastic interlayer are assembled in the form of a sandwich in an arearemote from the bending lehr. The bent glass sheets are usually cooledto a temperature approaching room temperature during their transfer toan assembly area. Therefore, they form a cool sandwich of sheets thatare able to slide relative to one another. To avoid sliding, thesandwich must be heated to a temperature at which the interlayer becomestacky and resists relative sliding.

The heated sandwich is subjected to a preliminary pressing by passingthe sandwich between one or more pairs of nipper rolls formed ofresilient, yet frictional, contacting material that engage the outersurfaces of the assembly to be laminated. As the sandwich passes throughthe nipper rolls, air entrapped between the layers of the assembly isforced out. This preliminary pressing, sometimes followed by edgerolling of the margin of the plastic interlayer before the latter coolsto room temperature, provides a sufficient seal extending over theentire marginal area of the assembly to prevent oil penetration and theresulting discoloration when the assembly is subjected to its finalpressing operation in the oil autoclave. A typical roll pressingapparatus for prepressing glass-plastic sandwiches is disclosed in U.S.Pat. No. 3,351,001 to Achkio.

At times, some portion of the plastic sheet adjacent the edge of thelaminate is not sealed to the glass after the prepassing operation, sothat in the final pressing operation oil can enter the laminate. Toalleviate this condition, any portions of the edge that are not sealedafter prepressing are manually edge sealed to prevent the oil fromentering the laminate during the final pressing operation. This edgesealing is accomplished immediately after prepressing by rolling andcompressing the hot interlayer edge, so as to force it between the glasssheets into sealing contact therewith, with a thin metal disc known inthe trade as an edge roller. A preferred edge roller is described inU.S. Pat. No. 2,999,779 to Morris.

The usual autoclave treatment utilizes temperatures ranging from about190° to 325° F. (88° to 163° C.) preferably about 225° to 300° F. (107°to 149° C.) and, simultaneously, elevated pressure in the range of 100to 250 pounds per square inch (0.7 to 1.7 megapascals) and preferably175 to 225 pounds per square inch (1.2 to 1.5 megapascals) for a periodof ten minutes to more than one hour, preferably 20 to 45 minutes. Whileoil autoclaves have been used more frequently in the past, finallamination has been accomplished by immersing prepressed assemblies inair autoclaves at approximately the same temperature and pressureconditions as those that prevail in oil autoclaves.

In the past, glass sheets were bent in pairs at one part of a windshieldfabrication plant and assembled, prepressed, edge rolled and subjectedto autoclave conditions in other parts of the plant. When sandwiches areassembled manually, it is convenient to allow the bent glass sheets tocool to a temperature suitable for handling before performing thesandwich assembly step. Such cooling wastes the residual heat in thebent glass sheets. It would be desirable for the assembly of thesandwich to take place at a time and place such that the energypresently lost through cooling the glass sheets between the bendingoperation and the assembly of the sandwich is not wasted so that thesandwich can be assembled, prepressed and edge-rolled using as much ofthe residual heat from the bending operation as possible. If thesandwich assembly is performed automatically, there is no need to beconcerned with operator discomfort that relates to handling hot glasssheets.

It would be desirable to perform the sandwich assembly stepautomatically rather than manually to provide a more consistentalignment of the sheets comprising the sandwich prior to their assemblywhile hot than is possible from assembling the sandwich by hand. When aflexible sheet of interlayer material is assembled between a pair ofbent glass sheets at an elevated temperature at which the interlayersurfaces become tacky on contact with hot glass and is unable to sliderelative to the hot glass it contacts, the sandwich remains in itsoriginally assembled configuration during subsequent treatment stepsincluding the prepressing operation using pressing rolls. Sinceautomatic assembly provides more repetitive alignment than manualassembly, the chance of breakage due to misalignment of the bent glasssheets of the sandwich during roll pressing required for prepressing isminimized provided automatic assembly apparatus is provided with meansto align the assembly position of the flexible sheet of interlayermaterial with those of the two bent glass sheets.

For the sake of this description, the term "bent glass sheet pair"refers to a pair of bent glass sheets without an interlayer sheet, theterm "subassembly" is used to identify a partial sandwich of a singleglass sheet and an interlayer sheet, the term "sandwich" comprises twomatched bent glass sheets and a flexible sheet of interlayer material,the term "assembly" is applied to a sandwich that has been prepressedand is ready for final lamination, and the terms "laminate" and"laminated windshield" are applied to the finally laminated assemblyafter the latter is subjected to an autoclave operation.

2. Description of Patents of Interest

U.S. Pat. No. 2,920,989 to Cochran et al. describes an automaticassembly apparatus for assembling a pair of bent glass sheets to form asandwich of the glass sheets with a sheet of interlayer material. Thebent glass sheets are separated and move at equal velocities along anassembly line where a sheet of interlayer material is applied to theupper surface of the lower bent glass sheet and the upper glass sheet isthen pivoted onto the upper surface of the interlayer to assemble asandwich for lamination. This operation is performed in an area remotefrom the location where the glass is bent. Consequently, the glassretains little, if any, residual heat from bending to assist inassembling the sandwich. Therefore, the sandwich must be reheated forthe prepressing and edge rolling steps.

U.S. Pat. No. 2,205,003 to Walters describes an apparatus for assemblinga sandwich of two flat glass sheets and a sheet of interlayer material.The glass sheets are of rectangular outline and are mounted on tablespivotable between a horizontal and a vertical orientation. After theglass sheets are mounted in the horizontal orientation, the tables arepivoted upon pivot axes located at the adjacent ends of the table, asheet of interlayer material is inserted therebetween and the assemblyis formed in a vertical orientation. The assembled sheets are thenpivoted in unison beyond the vertical orientation so that the assemblycan then be removed. This patent does not treat bent assemblies nor doesit treat assemblies in which any of the components remain heated from aprevious operating step.

U.S. Pat. No. 3,499,744 to Tolliver suggests using residual heat inrecently bent glass sheets to help secure a small metal bracket thatsupports a rear view mirror to a glass surface. The metal bracket iscoated with a thermoplastic adhesive on the surface bonded.

U.S. Pat. No. 3,518,137 to Hamilton discloses apparatus for assembling asafety glass panel, also of flat safety glass, and provides a wedgemeans that moves in advance of a pair of nipper rolls to insure that airis selectively removed from the interfacial surfaces of the assemblyduring its fabrication. While the patent refers to the application ofheat and pressure when an interlayer is self-securing at elevatedtemperatures, there is no suggestion in this patent of using the heatremaining from a previous operation, such as shaping the glass sheets,to help bond adjacent layers of an assembled sandwich to one another.

Since a specific embodiment of the present invention involves the use ofvacuum supports, a novelty search reported U.S. Pat. No. 2,317,348 toWekeman, which discloses a vacuum holder in which sheets are supportedby vacuum around their perimeter. Another patent cited was U.S. Pat. No.3,833,251 to Creskoff, which discloses a vacuum lifter to supportarcuately shaped objects. The lifter is provided with a pair of flexiblesheets, one of which is reinforced with a central stiffening member thathelps prevent undesired bending of a flexible sheet having a portthrough which a vacuum source communicates to provide the vacuum forlifting objects of arcuate shape. Another vacuum suspension device forhandling large sized plates is reported in U.S. Pat. No. 4,155,583 toMikos et al. The apparatus of this patent comprises a vacuum chamberdivided into two parts, a larger work chamber forming a vacuum containerconnected with pumps and a smaller decompression chamber situated belowthe working chamber. Both chambers are connected together byelectromagnetic valves to provide a quicker operation. This vacuumsuspension apparatus is particularly useful in handling concretebuilding parts that are of low strength and brittle.

U.S. Pat. No. 3,638,564 to Prange et al. discloses means to orient andalign a flat glass sheet of non-rectangular outline on a conveyor belt.This patent provides side edge engaging discs movable in pairs to engagethe opposite side edges of the glass sheet and end edge engaging discsthat move in pairs against the opposite end edges of the flat glasssheets in a horizontal plane common to the discs to properly align eachsheet both transversely and longitudinally of the conveyor belt at afixed station.

SUMMARY OF THE INVENTION

The present invention is performed using apparatus concerned with theassembly of a sandwich with minimum fuel consumption to insure that theflexible sheet of interlayer material tacks onto both bent glass sheetsas described and claimed in the aforesaid U.S. patent application Ser.No. 287,595 of James L. Valimont. It also concerns assuring that alaminated windshield having good optical properties results. However,the principles of the present invention may also be used to assemble asubassembly which may be fabricated into a bilayer windshield comprisinga single bent glass sheet laminated on one surface to a flexible sheetof plastic material.

The illustrative embodiment of the present invention involvesautomatically assembling a pair of bent glass sheets of matchingcurvature with a flexible sheet of plastic interlayer material to form asandwich to be laminated in such a manner that the residual heatresulting from the glass sheet bending operation is not completelywasted. The bent glass sheets and the sheet of interlayer material areassembled automatically to form a sandwich for the prepressing operationand the edge rolling operation (should the latter be needed) in thevicinity of the exit of a glass sheet bending lehr where the glasssheets are bent in pairs to assemble a sandwich of a flexible sheet ofinterlayer material with a pair of bent glass sheets while hot.

Various specific features of the specific embodiment of an assemblymethod and apparatus are covered either in the present application or inclosely related copending patent applications. These include the presentinvention of James L. Valimont and Hershel L. Phares covering the mannerin which the flexible interlayer sheets are handled prior to sandwichingone of them between a pair of bent glass sheets of matchingconfiguration at a sandwich assembly station.

In this specific embodiment such as is described and claimed in thepresent patent application, the flexible interlayer sheet is mounted inproper alignment over a curved vacuum mold having an apertured wallshaped to conform to the shape of the bent glass sheets while the shapedwall is oriented to a convex elevation. The vacuum mold is then rotated180 degrees with vacuum applied to hold the sheet of flexible interlayermaterial in a concave elevational configuration against the mold. Thebent glass sheets oriented to have a concave elevation are separated toprovide a gap for inserting the sheet of the interlayer material betweenthe bent glass sheets so that the vacuum mold moves into a positionwhere its shaped apertured wall is between the separated bent glasssheets and then is moved toward the lower bent glass sheet to depositthe sheet of interlayer material in proper alignment over the lowerglass sheet.

The vacuum mold is then pressurized to help transfer the interlayersheet as quickly as possible onto the lower bent glass sheet to form asubassembly. The vacuum mold is removed from the assembly station assoon as the subassembly of the lower glass sheet and sheet of interlayermaterial is formed.

The upper bent glass sheet then moves into a position of alignment withthe subassembly to engage the interlayer sheet to complete the sandwichwhile still hot enough to make the interlayer sheet tacky on contact ascovered by the invention of James L. Valimont described and claimed incopending patent application Ser. No. 287,595. The vacuum mold of thepresent invention is rotated to a convex elevational configuration toone side of the assembly station to load another flexible sheet ofinterlayer material for use in the next sandwich to be assembled.

The assembled sandwich leaves the assembly station for a furtherprocessing station, which, in this case, is a roll pressing station. Toinsure against mismatch of the flexible interlayer sheet relative to thevacuum mold and also to compensate for dimensional changes in the sheetof flexible interlayer material, the latter sheets are preferably cut toslightly larger dimensions than the bent glass sheets forming thesandwich or subassembly to be assembled.

Another feature of the specific embodiment of apparatus covered incopending U.S. patent application Ser. No. 287,600 of James L. Valimontand Joseph B. Kelly involves the use of a plurality of vacuum cups forsupporting the bent glass sheets. The vacuum cups are mounted andoriented in a lower set and an upper set. The cups in each set move inunison so that the lower set engages the bottom surface of the lowerbent glass sheet in flatwise engagement against localized engaged areasand the upper set engages the top surface of the upper bent glass sheetin a similar flatwise engagement. When vacuum is applied to the vacuumcups and the sets are separated, they separate the two glass sheets toprovide a clearance gap for moving a sheet of flexible interlayermaterial into the assembly position within the gap while the flexiblesheet is engaged by vacuum by a vacuum mold having an apertured sheetengaging wall shaped to conform to the bent glass sheets.

In a specific embodiment of this feature of inventive subject matter,each set of vacuum cups is preferably of the type described and claimedin the aforesaid copending patent application Ser. No. 287,600 of JamesL. Valimont and Joseph D. Kelly, and is mounted along a surfacegenerally parallel to the surface defined by the engaged bent glasssheets. However, the lower set of vacuum cups includes at least oneupwardly biased, central vacuum cup that engages the central portion ofthe lower glass sheet relative to the other vacuum cups of the lower setto provide a slight, temporary upward bias to the central portion of thelower glass sheet when the lower set initially engages the bottomsurface of the lower glass sheet. Thus, when the vacuum mold is loweredto apply the flexible interlayer sheet against the top surface of thelower bent glass sheet, the interlayer initially makes contact with theslightly upwardly biased central portion of the lower bent glass sheet,the lowering mold gradually overcomes the upward bias of the centralportion and gradually increases the area of contact outward from thecentral portion of original contact with the lower bent glass sheettoward the outermost longitudinal ends of the glass sheet to force airalong the interface toward the edge of the resulting subassembly.Removing the vacuum mold reinstitutes the temporary upward bias in thecentral portion of the lower glass sheet, so that when the upper glasssheet is installed in superimposed position over the subassemblycomprising the biased bottom glass sheet and the interlayer sheet, thebottom surface of the upper glass sheet makes initial contact with thetop surface of the interlayer sheet at its central portion superimposedon the temporarily upwardly biased central portion of the lower glasssheet and the upward bias is gradually overcome as the upper glass sheetis lowered. In this manner, the area of contact gradually increasesoutward from the central portion between the bottom surface of upperbent glass sheet and the top surface of the interlayer sheet toward theopposite longitudinal ends of the sheets to force air along the newlyformed interface toward the edges of the resulting sandwich. This aspectof inventive subject matter is believed to cover the assembly of thesubassembly as well as that of the sandwich.

Another feature of the preferred embodiment to be covered in the presentpatent application involves a lightweight vacuum mold having anapertured wall shaped to conform to the top surface of the lower glasssheet, a second wall of similar shape and a plurality of relativelyclosely spaced blocks of uniform thickness separating the shaped wallsto insure that the walls of the vacuum mold remain uniformly spaced fromone another, while providing a vacuum mold of minimum mass and desiredshape. The lightweight vacuum mold moves between an orientation ofconvex elevational configuration for applying the flexible interlayersheet onto the mold at a mold loading station and an orientation ofconcave elevational configuration at an assembly position aligned withpositions of alignment for at least one of the bent glass sheets at anassembly station.

Still another feature of inventive subject matter contained in thepreferred apparatus embodiment involves means to insure the alignment ofthe top and bottom bent glass sheets before they are separated from oneanother to an alignment position that the flexible sheet of interlayermaterial occupies at the assembly station, and to insure that they arein proper alignment while the sandwich is assembled. The alignment meansis an invention of James L. Valimont and Barry L. Shadle described andclaimed in the aforesaid copending patent application Ser. No. 287,600and comprises longitudinal end edge alignment means and side edgealignment means . The end edge alignment means comprises a pair oflinear rotating rolls to engage each longitudinal end edge of the glasssheet pair, means to orient each of said pairs of linear rotating rollsto be parallel to an adjacent end edge portion of the glass sheets, andmeans to move said pairs of linear rotating rolls in essentiallyhorizontal paths spaced vertically from the support plane of theconveyor.

The linear rotating rolls of the end edge alignment means are freelyrotatable about axles that extend obliquely in directions approximatelyparallel to the end edge surfaces of bent sheet pairs having a curvatureabout a transverse axis within a given range of curvatures. The orientedpairs of linear rotating rolls have an axial length sufficient to engagespaced end edge portions of pairs of bent glass sheets having a depth ofbend within a given range of depths of bend when moved in unison alongsaid essentially horizontal paths.

The side edge alignment means comprise a pair of side edge alignmentrolls adapted to engage each side edge of said glass sheet pair bymoving at least one of said pair of side edge engaging rolls andpreferably both of said pairs of side edge engaging rolls transverselyto define a transverse alignment position of support along the conveyor.Then, the side edge engaging rolls move vertically while maintainingside edge engagement as the pair of bent glass sheets is lifted off theposition of support along the conveyor.

The linear rotating rolls of the end edge engaging means are oriented inpairs of freely rotatable end edge engaging rolls. Each roll pair ismounted to pivot for pivotable adjustment to a desired fixed orientationabout a common axis for the roll pair of position said linear rotatingrolls along a line parallel to the longitudinal end edge of the bentglass sheet pair adjacent thereto. Each linear rotating roll is freelyrotatable about an obliquely extending axis approximately parallel tothe corresponding end edge of the bent glass sheets of a family ofpatterns to be aligned and assembled into sandwiches. The rolls of theedge alignment means orient and align the bent glass sheet pair as apair relative to the support provided by spaced conveyor rolls prior tothe engagement of the upper end lower bent glass sheets by upper andlower sets of vacuum cups that engage the upper and lower glass sheetsof the pair after the lower set lifts the bent glass sheets off theconveyor support. The vacuum cups maintain the orientation and alignmentof the bent glass sheets relative to an assembly station after the edgealignment rolls are separated from the engaged edges.

The gist of the present invention relates to a vacuum mold having ashaped apertured wall and a method of using said vacuum mold to assemblea sheet of flexible interlayer material with one or more bent glasssheets. The best mode of this invention is combined with the otherinventive subject matter of the closely related applications describedherein to provide the best mode for the invention of James L. Valimontdescribed and claimed in copending U.S. patent application Ser. No.287,595.

The benefits of the assembly apparatus and the features claimed in thiscase will be appreciated in the light of a description of a preferredembodiment that incorporates the claimed features that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings that form part of the description of the preferredembodiment, and wherein like reference numbers are used to depict likestructural elements.

FIG. 1 is an isometric, schematic view of a station for assembling asandwich of a flexible plastic interlayer (not shown) between a pair ofbent glass sheets, shown separated, showing how the assembly station islocated in close relation to a glass sheet bending lehr with a crossconveyor for conveying bent glass sheets from said bending lehr intosaid assembly station and in close relation to a vacuum mold loadingstation for applying a sheet of flexible interlayer material thereon fortransfer to the assembly station while supported on the mold, withcertain parts omitted to show other parts more clearly;

FIG. 2 is a front elevational, structural view of an empty assemblystation of the present invention, with upper and lower sets of vacuumcups for supporting bent upper and lower glass sheets retracted and ashaped vacuum mold oriented in a convex elevational configuration formounting a sheet of flexible interlayer material thereon, with partsomitted to show other parts more clearly;

FIG. 3 is a side elevation of the empty assembly station bepicted inFIG. 2, with some parts broken away and some parts omitted to showcertain parts more clearly;

FIG. 4 is a top plan view of the empty assembly station depicted inFIGS. 2 and 3 with some parts broken away to show other parts;

FIG. 5 is a horizontal sectional view of the lower portion of theassembly station taken along the line 5--5 of FIG. 2;

FIG. 6 is an enlarged detailed view of a lower end vacuum cup and itssupporting structure showing how the vacuum cup can be adjusted andtilted;

FIG. 7 is a view taken at right angles to the view of FIG. 6;

FIG. 8 is an enlarged detailed view of a lower middle vacuum cup showinga spring loaded connection to its support structure;

FIG. 9 is an enlarged detailed view of one of the upper vacuum cupsshowing how it is mounted along an oblique axis relative to an uppervacuum cup support means;

FIG. 10 is an enlarged plan view of an end edge guide means oriented forguiding glass sheets of non-rectangular outline and apparatus foractuating movement of said end edge guide means;

FIG. 11 is a side elevation of the structure shown in FIG. 10;

FIG. 12 is an end elevation of the structure shown in FIGS. 10 and 11;

FIG. 13 is a plan view of a vacuum mold having a curved apertured wallconforming to the shape of the bent glass sheets, with parts of one wallbroken away to show parts of an apertured wall and the arrangement ofcertain spacer elements that are distributed throughout the vacuum mold;

FIG. 14 is a partial cross-section and partial side elevation takenalong the line 14--14 of FIG. 13; and

FIG. 15 is a cross-section of a rack and pinion type of rotary actuationfor pivoting the vacuum mold, taken along the line 15--15 of FIG. 2;

FIG. 16 is a schematic front elevation view of the assembly stationshowing a bent glass sheet pair supported on a cross conveyor at theassembly station at the early stage of an assembly cycle;

FIG. 17 is a fragmentary schematic side elevational view of the assemblystation also showing a vacuum mold loading station taken at the momentdepicted in FIG. 16;

FIG. 18 is a view similar to that of FIG. 16 taken at an intermediatestage in the cycle of operation of the assembly station of thisinvention;

FIG. 19 is a view similar to that of FIG. 17 taken simultaneously withFIG. 18;

FIG. 20 is a view taken after the view of FIG. 18 and similar thereto,showing the assembly station in a late stage of operation; and

FIG. 21 is a view similar to that of FIG. 19, showing a side view of theassembly station at the moment depicted in longitudinal elevation inFIG. 20.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The various inventions incorporated in this specification will be betterunderstood in the light of a description of a preferred embodiment whichfollows. In the preferred embodiment, the apparatus of the presentinvention is shown in an environment in which it is used to assembly asandwich of a bent glass sheet pair including an upper bent glass sheet11 and a lower bent glass sheet 12 with a flexible sheet 14 ofinterlayer material assembled in unwrinkled relation therebetween.

The sheets used to form the sandwich have similar outlines. Since theinterlayer material shrinks and expands diffentially during thermaltreatment required for lamination to glass sheets, it is preferred tocut the flexible sheets 14 of interlayer material to outline shapeshaving slightly larger dimensions than those of the bent glass sheets 11and 12. The flexible sheets 14 are preferably made approximately 3/8inch (10 millimeters) longer and 1/4 inch (6 millimeters) wider than thecorresponding dimensions of the bent glass sheets 11 and 12 to provide aborder of flexible interlayer material extending about 3/16 inch (5millimeters) beyond each longitudinal end and about 150 inch (3millimeters) beyond each transverse side of the glass sheets betweenwhich they are assembled.

As best seen in FIG. 1, the environment comprises a bending lehr 30 oftunnel-like configuration having a lehr exit 32. A plurality of bendingmolds and carriage assemblies 34 traverse the bending lehr 30 and passthe lehr exit 32 onto a glass sheet unloading station 36 to which theyare conveyed by a plurality of lehr conveyor rolls 38. The bending lehris typical of the prior art.

Immediately to one side of the unloading station 36, the upstream end ofa cross conveyor 40 is located. The cross conveyor 40 extends from itsupstream end adjacent the unloading station 36 along a path over a shortdistance slightly longer than the longest of glass sheets to beprocessed and intersects an assembly station 42 to one side of which islocated a vacuum mold loading station 43. The cross conveyor continuesalong a continuation of said path through a roll pressing apparatus 44and beyond to an unloading station (not shown).

The assembly station 42 of the present invention comprises a supportframe 45 (FIG. 2) adjustably supporting an open-sided table 46 forvertical movement. Table 46 comprises a horizontal plate 46a and abox-like frame 46b. The latter is provided with vertical guide rods 47that slide in collars 48 (fixed to the support frame 45) to guide thetable for vertical movement. A piston rod 49 extending upwardly from avertically oriented piston cylinder 50 is connected to the horizontalplate 46a to move the table 46 vertically between a lower position belowcross conveyor 40 and an upper position. The cylinder is rigidly mountedon a bracket 51 that is rigidly supported on the support frame 45.

A plurality of externally threaded vertical rods 52 (FIGS. 2, 3, 6 and7) are adjustably attached to the table 46 by extending through alignedopenings in the horizontal plate 46a and the box-like frame 46b andsecured thereto by lock nuts 53. Each vertical rod 52 is attached to anangle member 54 at its upper end. Each angle member 54 comprises anarcuately slotted and apertured vertical flange 56, whose arcuate slotis indicated at 55, and a horizontal flange 58. A lower radial bolt 57is fixed to the vertical rod 52 and extends through the arcuate slot ofthe arcuately slotted flange 56. An upper radial bolt 59 is fixed to thevertical rod 52 and extends parallel to the direction of the lowerradial bolt 57 through an upper aperture of the slotted and aperturedflange 56. Tightening nuts are provided to secure the lower radial bolt57 in a desired position along the arcuate slot in the arcuately slottedflange 56 and to secure the upper radial bolt 59 in the aperture offlange 56. The angle members 54 are free to pivot about axes defined bythe upper radial bolts 59 as limited by the length of the arcuate slots55 when the bolts 57 and 59 are unsecured.

An externally threaded drilled out rod 60 is fixed to the horizontalflange 58 of each angle member 54. An end lower vacuum cup 62 is fixedto the upper end of the drilled out rod 60. In this manner, both thevertical position and the orientation of the end vacuum cups 62 can beadjusted so that the mean plane of the vacuum cup is parallel to thetangent of the bottom surface of the lower bent glass sheet 12 in thevicinity of the associated end lower vacuum cup 62. The orientation ofeach end vacuum cup is changed by loosening the arcuate slot connectionand repositioning the bolts to another position along the arcuate slotand tightening the bolts of the corresponding angle member 54.

The vacuum cups are made of rubber and a preferred size is 4 inches (10centimeters) in diameter. A preferred durometer for the vacuum cups is45 Shore A. The end vacuum cups 62 are arranged in transversely alignedpairs located to engage a shaped glass sheet near each of its oppositelongitudinal ends in transversely spaced areas.

An additional pair of lower central vacuum cups 63 similar inconstruction to the end vacuum cups 62 are also mounted to the upperends of additional drilled out rods 60, which are mounted on additionalangle members 54, which are disposed toward the center of the box-likeframe 46b. Vacuum cups 62 and 63 serve as a lower set of flexiblesupport members comprising a pair of transversely spaced end lowervacuum cups 62 at each end portion of an assembly area and a pair oftransversely spaced central lower vacuum cups 63 at the central portionof the assembly area. The lower set of vacuum cups are located generallyalong a surface conforming to the shape of the bent glass sheets exceptfor a slight upward biasing of the central lower vacuum cups 63. Thelower set of vacuum cups 62 and 63 serve as a first set of flexiblesupport members.

The middle angle members 54 are arcuately adjustable relative to avertical rod 64 (FIG. 8), which is mounted in spring-loaded relation tothe table 46 through a compression spring 66, which bears against abushing 67 at its lower end and an upper of a pair of spring adjustmentnuts 68 at its upper end. The vertical rods 64 extend through alignedopenings in the central portions of box-like frame 46b and plate 46a andare locked at their lower ends to the table 46 by lower bushings 67 andlock nuts 68.

The spring 66 is so constructed and the vertical position of thevertical rod 64 is adjusted relative to the positions of adjustment ofthe end lower vacuum cups 62 that the middle lower vacuum cups 63 wouldoccupy positions along a curved surface occupied by said end lowervacuum cups that is generally parallel to the shape of the lower bentglass sheet 12 except when springs 66 provide an upward bias to themiddle lower vacuum cups 63 that bias the latter upwardly from thegenerally parallel surface for reasons to be explained later.

A flexible vacuum hose 69 is attached to each drilled-out rod 60 toprovide a path to a source of vacuum (not shown). The hose 69 is alsoprovided with a valved connection to transfer the path of communicationwith a vacuum source to one communicating with a source of pressurizedair (not shown).

The vacuum cups 62 and 63 are located in spaces between adjacentconveyor rolls of the cross conveyor 40. This permits the lower set ofvacuum cups 62 and 63 to move vertically in unison through thediscontinuous plane of support provided by the rolls of cross conveyor40 while maintaining their relative alignment and individual orientationon actuation of the piston rod 49 in vertically oriented piston cylinder50. The upper and lower vertical positions of the piston rod arecarefully controlled so that the lower set of vacuum cups 62 and 63 isbelow the level of cross conveyor 40 when the piston rod 49 isretracted, its uppermost position is defined by the height needed tolift the pair of bent glass sheet to enable the top surface of the upperglass sheet 11 to engage an upper set of vacuum cups at the upperposition while the lower set of vacuum cups supports the lower bentglass sheet at a position where a flexible sheet of interlayer materialis applied thereto at the assembly station 42.

The cross conveyor 40 is supported on a conveyor support structure 70(FIG. 3) having a plurality of vertical columns 71 and 72 along eachside of the cross conveyor. The vertical columns support bearinghousings for horizontally disposed conveyor rolls in a manner well knownin the art. The conveyor rolls are arranged in sections to move in acontrolled sequence in a manner well known in the conveyor art. A pairof adjacent vertical columns 71 also supports a bracket 73 on which ismounted a first horizontal cylinder 74 from which a piston rod 75extends. A clevis 76 (see FIG. 5) is attached to the outer end of thepiston rod 75, and in turn is attached to the middle of a cross arm 77.The ends of the cross arm 77 are mounted in horizontal guides (notshown) to insure that the cross arm 77 moves in a horizontal directionon actuation by piston rod 75. A pair of vertical guide rods 78 (FIG. 3)extend upward from the cross arm, one on each side of the clevis. Eachguide rod 78 has a reduced, elongated upper portion 79 that receives afreely rotatable and vertically slidable linear guide roll 80 forengaging one side edge of a glass sheet during an assembly operation.This engaged side becomes the bottom side edge of the installedwindshield. The guide rolls 80 will be referred to as the bottom sideedge alignment rolls.

Mounted in similar manner to bracket 73, a pair of adjacent verticalcolumns 72 supports a bracket 82. A second horizontal cylinder 83(opposed to cylinder 74) containing a piston rod 84 (similar to pistonrod 75) is mounted thereon. A clevis 85 is attached to piston rod 84 atthe middle of a cross arm 86, similar to the attachment of clevis 76 topiston rod 75 at the middle of cross arm 77. A pair of vertical guiderods 87 similar to vertical guide rods 78 with reduced upper portions 88(similar to reduced upper portions 79) support guide rolls 89 in amanner similar to the support of guide rolls 80. Guide rolls 89 arecalled the top side edge alignment rolls because they engage the sideedge of the glass that becomes the top side edge of the installedwindshield. Guide rolls 80 and 89 are preferably composed of a materialthat does not harm glass such as soft rubber. A Shore A durometer of 50to 55 is suitable for the side edge guide rolls 80 and 89.

Piston rods 75 and 84 move the pairs of side edge guide rolls 80 and 89between laterally recessed positions and controlled glass side edgeengaging positions against the opposite side edges of the bent glasssheet pair or of the lower bent glass sheet 12 to align the glass sheetstransversely of one another and on opposite sides of a verticallyextending space that intersects a desired assembly position within theassembly station. The free vertical sliding of guide rolls 80 and 89along the reduced upper portions 78 and 87 of the guide rods 78 and 87maintains the glass sheets in transverse alignment within saidvertically extending space as long as the guide rolls 80 and 89 engagethe side edges of the glass sheets. The free vertical slidingarrangement permits the side edge engaging guide rolls 80 and 89 to fallby gravity to positions defined by the wider, lower portions of theguide rods 78 and 87, which serve as stops. The latter enable the sideedge alignment rolls 80 and 89 to intersect the horizontal plane ofsupport provided by the rolls of the cross conveyor 40 when the sideedge engaging rolls 80 and 89 are laterally retracted and slid down onthe vertical guide rods 78 and 87.

Two pairs of upper vacuum cups 90 are adjustably mounted relative to anapertured plate 91 for adjustment along axes extending obliquely of theplate. The upper vacuum cups 90 are located near the oppositelongitudinal ends of the vertically extending space that a pair of bentglass sheets occupies during an assembly operation, and need not opposethe lower vacuum cups 62 or 63. The upper vacuum cups 90 serve as anupper or second set of flexible support members and are oriented to facea curved surface parallel to the curved surfaces defined by the pair ofbent glass sheets and also parallel to the curved surface defined by theend lower vacuum cups 62 and the middle lower vacuum cups 63 when thelatter are not biased upwardly.

As seen in FIG. 9, the mounting for each vacuum cup 90 comprises athreaded shaft 92 that is drilled axially for at least a portion of itslength to provide an evacuation or pressurized air supply passage, apair of lock nuts 93 disposed on opposite sides of apertured plate 91and a pair of bevelled washers 94 having complementary bevels disposedon either side of the apertured plate 91 in position to receive thedrilled threaded shaft 92 that extends through an aperture of theapertured plate 91. A vacuum hose 69 communicates with the drilledportion of the threaded shaft 92 to communicate each upper vacuum cup 90with a vacuum source or a source of pressurized air through suitablevalve means (not shown).

The upper vacuum cups 90 may be made of the same size, material andconstruction as the lower vacuum cups 62 and 63. Turning thecomplementary bevelled washers 94 about the axis of shaft 92 enables oneto orient the plane of each upper vacuum cup 90 to bring the associatedcup in flatwise relation relative to the tangent to the top surface ofthe upper bent glass sheet 11 in the area of engagement.

The orientation of the upper vacuum cups 90 may also be changed whenrequired to conform to different glass sheet shapes by disassembling thethreaded shafts 92 from the apertured support plate 91, removing the setof bevelled washers 94 and reassembling the threaded shafts 92 to theapertured plate with complementary bevelled washers having a differentbevel from those removed. Using either method, the orientation of theupper vacuum cups 90 is arranged to have the vacuum cups 90 parallel tothe mean datum plane of the bent glass sheet in the portion of the topsurface of the upper glass sheet that it engages and to have the upperset of vacuum cups 90 supported generally along a curved surfaceparallel to the contour of the bent glass sheets 11 and 12.

A pair of shaft rail supports 95 is connected to the upper side of plate91, as seen in FIGS. 2, 3, 10, 11 and 12. Each shaft rail support 95supports a longitudinal rail 96, described as longitudinal as it extendslongitudinally of the path defined by the cross conveyor 40.

A clevis 97 attaches the upper surface of apertured plate 91 to thelower end of a vertically extending piston rod that moves relative to avertical piston cylinder 98. Three vertical guide rods 99 also extendvertically upward from apertured plate 91 through fixed bearing housings100 to help guide movement of plate 91 in a vertical direction inresponse to movement of the piston rod in piston cylinder 98. The fixedbearing housings 100 are securely attached to a support plate 101extending across the bottom of a superstructure 102. The support plate101 also supports the piston cylinder 98. It is apparent that thisarrangement causes the upper vacuum cups 90 to move as a set within thevertically extending space defined by the outlines of properly alignedbent glass sheets 11 and 12 in response to actuation by the pistonextending from piston cylinder 98 without changing the orientation orrelative position of each upper vacuum cup 90 relative to the othervacuum cups 90 of the upper set. Therefore, when a properly alignedupper bent glass sheet 11 engages the upper set of vacuum cups 90, theupper bent glass sheet is incapable of becoming misaligned and/ormisoriented while it remains engaged by the upper vacuum cups 90 andmoves in unison with the vacuum cups 90 in a vertical direction withinthe vertically extending space.

Movement of the piston operating from the vertical piston cylinder 98 iscontrolled between an upward position wherein the upper set of vacuumcups 90 are supported along a curved surface generally parallel to theupper position of the upper bent glass sheet 11 when the latter engagesthe upper set and a lower position wherein the upper bent glass sheetheld thereagainst is moved downward to the vicinity of the top surfaceof the lower glass sheet 12 supported by the lower set of vacuum cups intheir intermediate positions.

Another feature of the illustrative embodiment of assembly apparatuscomprises longitudinal end edge alignment means. While the particularend edge alignment means described is for use to align non-parallel orparallel longitudinal edges of hot bent glass sheets, it is understoodthat this longitudinal end edge alignment means is also suitable for usein aligning one or more bent glass sheets at temperatures different thanthe residual temperature of the bent glass sheets.

Also attached to the upper surface of plate 91 are a pair of horizontalcylinders 103 (only one of which is shown in FIGS. 10, 11 and 12). Thecylinders 103 (also shown in FIG. 4) extend longitudinally of the crossconveyor 40 in opposite directions with piston rods 104 extendinglongitudinally upstream and downstream relative to cross conveyor 40. Aclevis 105 (FIGS. 10 and 12) attaches the outer end of each piston rod104 to an arcuately slotted plate member 106. The latter is pivotallyattached to a bearing support member 107 through a pivot pin 110 (FIGS.4, 10, 11 and 12). The member 107 has bearing housings 108 (FIGS. 11 and12) extending downward from its lower surface in such a manner that eachpair of bearing housings slidably engages one or the other longitudinalrails 96.

An eye member 109 (FIG. 12) extending through an aperture in platemember 106 is fixed to bearing support member 107 and is attached to theclevis 105 (FIG. 12). The arcuately slotted plate member 106 alsoreceives the pivot pin 110 in such a manner that the arcuately slottedplate member 106 is free to rotate in a horizontal plane about avertical pivot axis defined by eye member 109. Layers 111 (FIG. 12) of alow friction material, such as various halogenated polyethylenecompositions sold commercially under the trademarks PACTENE and TEFLON,are applied against the major surfaces of the arcuately slotted platemember 106 to facilitate its rotation. A pair of shoulder bolts 112(FIGS. 10 and 12) with suitable lock nuts extends through each of thearcuate slots 113 of the arcuately slotted plate member 106 and alignedbolt openings in the bearing support member 107 to fix the orientationof the arcuately slotted plate member 106.

A pair of angled supports 114 (FIGS. 2, 3, 11 and 12) is rigidlyattached to each arcuately slotted plate member 106 and terminates in aroll housing 150 (FIGS. 10 to 12) that supports an obliquely extendingaxle 151 for supporting an end edge engaging roll in the form of alinear rotating roll 115 that is in free rotating relation with saidaxle and which has an axial length sufficient to engage the longitudinalend edge of glass sheet pairs having a range of depths of bend anddegrees of curvature within a family of patterns for which the apparatusis designed. Piston rods 104 (FIGS. 4 and 10) actuate longitudinalmovement of the linear rotating rolls 115 between carefully controlledpositions of the piston rods that bring the rolls 115 toward and awayfrom engagement with one or the other opposite longitudinal end edges ofa bent glass sheet pair to form part of longitudinal edge alignmentmeans that either aligns the pair of bent sheets in proper longitudinalalignment with the assembly station 42 or retracts out of engagementwith said sheets. The linear rotating rolls are supported for movementin horizontal directions in a horizontal plane vertically spaced fromthe horizontal support defined by the rolls of the cross conveyor 40 andfrom the side edge alignment rolls 80 and 89.

The lines of orientation of the tangents common to the linear rotatingrolls 115 are shown in FIG. 10 in the orientation required to engageglass sheets of non-rectangular outline. However, these lines can beadjusted to conform to any desired oblique orientation of thelongitudinal end edge at the corresponding longitudinal end portion ofthe shaped glass sheets to be assembled by adjusting the orientation ofthe arcuately slotted plate member 106 relative to the bearing supportmember 107 about the pivot pin 110 (which serves as a common pivot axisfor a pair of linear rotating rolls 115) and locking the shoulder bolts112 securely along arcuate slots 113 when the arcuately slotted platemember 106 is in a desired orientation about said common pivot axis.

The linear rotating rolls 115 are free to rotate about the axles 151that are oblique to the vertical and approximately parallel to theorientation of the end edge surfaces of the most sharply bent glasssheets of the family of patterns for which the apparatus is designed.The linear rotating rolls can be used to align the longitudinal endedges of glass sheets bent to angles of bending ranging from the exactangle of sharpest bend to angles of approximately 45 degrees morecurvature than the angle of sharpest bend. In other words, the linearrotating rolls are mounted to rotate about oblique axes that extendupwardly and inwardly from the vertical at a minimum oblique angle thatis exactly parallel to the longitudinal edge surface of glass sheetsbent to a concave elevational configuration. The maximum oblique anglefor mounting the linear rotating rolls can exceed the minimum angle byas much as approximately 45 degrees, depending on the thickness anddifference in length between the upper and lower bent glass sheets ofthe pair being assembled. The rolls 115 are made of a soft rubbercomposition, preferably 50 to 55 Shore A durometer so as not to mar theglass edges on engagement therewith, even when the rolls 115 do not abutin exact parallel relation to the end edges of the glass. The length ofthe linear rotating rolls 115 is sufficiently long to permit the rollsto engage longitudinal end edges of bent glass sheet pairs that are bentto various depths of bend within the family of patterns for which theapparatus is designed.

Superstructure 102 is rigidly fixed to a pair of upper horizontal crossbeams 116 (FIGS. 1 to 4) of a main frame structure 117 by a pair oflongitudinal angles 118. Each of the horizontal cross beams 116 supportsa transverse horizontal rail 119. The latter rails extend between theassembly station 42 and the flexible interlayer sheet loading station43. A carriage 120 is suspended from rails 119 through bearing housings121. A piston from a cylinder 122 is connected through a clevis 123 to across member 124 forming part of the superstructure of the carriage 120.The piston 122 is pivotally mounted on the main frame structure 117 sothat its piston rod actuates movement of the carriage 120 along therails 119 between the vacuum mold loading station 43 and the assemblystation 42.

The carriage 120 has two depending brackets 125 (FIGS. 2 and 3) thatsupport a pair of longitudinally and horizontally aligned bearinghousings 126 (FIG. 2) that receive a pair of stub axles 127interconnected by a box-like housing 128 of rectangular cross-section. Amounting plate 142 is attached to housing 128 for rotation therewith. Arotary actuator (FIG. 15) comprises a pinion 129 operatively connectedto one of the stub axles 127 to rotate the box-like housing 128 and itsattached mounting plate 142 through an angle of 180 degrees about thehorizontal longitudinal axis defined by the stub axles 127. Referring toFIG. 15, the pinion 129 fixed to rotate with one of the stub axles 127engages an elongated rack 130 which substitutes for a piston rod forlinear movement relative to a piston housing 132 (FIGS. 1 and 2). Thelatter is supported on a lower horizontal beam of carriage 120. Linearmovement of the rack 130 causes pinion 129 to rotate, thereby causingthe box-like housing 128 and its mounting plate 142 to rotate about stubaxles 127.

A vacuum chamber 131 (FIGS. 13 and 14) has a convexly curved aperturedwall 133 having an array of apertures 134 and a concavely curved wall135. Both walls are constructed of 1/8 inch (3.1 millimeters) thickaluminum sheets. The sheets are separated by a rigid, shaped marginalseparator frame 136 and an array of spacers 137 formed of rubber blocks.The latter are distributed throughout the extent of the vacuum mold 131to maintain a space between walls 133 and 135 of uniform thicknessenclosed within the marginal frame 136.

The rubber spacers are one inch (2.54 centimeters) square and one-halfinch (1.27 centimeters) thick and are separated from one another to formcriss-crossing rows. Sufficient rigidity to maintain a space of constantwidth is provided with rubber blocks having a Shore A durometer of 55.The apertures 134 form a checkerboard array on one inch (2.54centimeters) centers and are 1/32 inch (0.8 millimeters) in diameter. Aseries of tightening bolts extend through the marginal separator frame136 and through aligned marginal apertures in walls 133 and 135 toprovide a tightly closed unitary vacuum mold.

As seen in FIGS. 2, 13 and 14, an eye 138 is welded to the geometriccenter of concavely curved wall 135 and engages a clevis 139 (FIG. 2).The latter is fixed to the end of a rod that extends from a pistonhousing 141. The latter is mounted to the box-like housing 128 andpasses through an opening in the mounting plate 142. The mounting plate142 supports a series of bearing housings 143 which receive alignmentpins 145. The latter extend from the concavely curved wall 135 of thevacuum mold 131 to which they are fixed. The rod from piston housing 141adjusts the distance of the vacuum mold 131 from mounting plate 142.When the piston from cylinder 122 extends, carriage 120 occupies aposition to support the vacuum mold 131 in proper longitudinal andtransverse alignment with the vertically extending space within whichcan be found the aligned bent glass sheets 11 and 12 at the assemblystation 42.

A vacuum stem 147 (FIGS. 13 and 14) extends from the concavely curvedwall 135 of the vacuum mold 131 and is connected to a line that isconnected through suitable valves (not shown) to either a vacuum sourceor a source of pressurized air, as desired during an assembly cycle. Ifdesired, a separate stem can be provided to connect directly to a sourceof pressurized air in combination with the vacuum stem 147.

When the rack 130 moves linearly with respect to pinion 129, the vacuummold 131 rotates with the box-like housing 128 and mounting plate 142.The length of the rack is such as to allow the vacuum mold 131 to rotate180 degrees about a horizontal axis defined by the stub axles 127. Thepiston within piston housing 132 controls the rotational movement of thevacuum mold 131 with the box-like housing 128 and mounting plate 142relative to the carriage 120 from an orientation wherein the aperturedwall 133 assumes a convex elevational configuration to one where theapertured wall assumes a concave elevational configuration.

In addition, the vacuum mold 131 moves with the carriage 120 between thevacuum mold loading station 43 to one side of the path of glass sheetmovement defined by cross conveyor 40 and the assembly station 42 acrossthe cross conveyor 40. The piston in housing 122 and clevis 123 actuatethis movement cycle through cross member 124 of the carriage 120.

Extension of the rod from piston 122 is inhibited until the rack 130moves to the end of its permitted movement at which time the vacuumchamber 131 rotates with mounting plate 142 to an orientation at whichthe curved apertured wall 133 has a concave elevational configurationand the upper set of vacuum cups 90 occupy their raised positions andthe lower set of vacuum cups 62 and 63 occupy their uppermost positions.The rod extends from piston 122 to move the oriented vacuum chamber 131into a position at the assembly station 42 where the vacuum chamber 131is directly aligned over the lower glass sheet 12. With the rod frompiston 122 fully extended, the rod from piston housing 141 is fullyextended to enable the flexible sheet 14 of interlayer material toengage the upper surface of the lower bent glass sheet 12. In order forthis desired alignment to take place properly, the glass edge engagingpositions of the linear rotating rolls 115 and side edge engaging rolls80 and 89 must be carefully adjusted by precise adjustments of thelocation and stroke of the actuating pistons that control the movementof the edge engaging rolls so that all four pairs of rolls 115, 80 and89 are in glass engaging positions that insure the alignment of thelower bent glass sheet 12 with the position of the vacuum mold 131 atthe assembly station 42 when the rod from piston 122 is fully extended.

Piston rod 49 actuates the lifting of the vertically movable table 46 inresponse to the arrival of a bent glass sheet pair at the assemblystation 42 along cross conveyor 40. The end lower vacuum cups 62 areoriented to face upward and inward so as to be in flat facing relationto different localized portions of the bottom surface of the lower glasssheet of the bent glass sheet pair. The upper vacuum cups 90 areoriented and arranged so that each upper vacuum cup 90 is aligned to bein flat facing relation to different localized portions of the topsurface of the upper glass sheet of the bent glass sheet pair. Themiddle lower vacuum cups 63 are oriented to be in flat facing relationwith different localized areas in the central portion of thelongitudinal dimension of the bottom surface of the lower glass sheet ofthe bent glass sheet pair and are biased upward by springs 66 to be afraction of the glass sheet thickness higher than the mean datum planeof the curvature defined by the bottom surface of the glass sheet at thelocalized areas of engagement. This arrangement biases the lower glasssheet upwardly a slight amount to guard against entrapment of air orother vapor when the flexible interlayer sheet 14 is applied against thetop surface of the lower bent glass sheet 12 when the subassembly ismade, and also when the upper bent glass sheet 11 is applied against thetop surface of the interlayer sheet when the subassembly is convertedinto a sandwich to be laminated. To further insure the ability of thesprings 66 to bias the lower middle vacuum cups 63 upwardly, the upperset of vacuum cups 90 has no vacuum cups in the central portion of thevertically extending space that intersects the assembly station 42.

Since the end lower vacuum cups 62 and the middle vacuum cups 63 aremounted onto the table 46 in fixed adjustment thereto, piston rod 49also actuates movement of the lower vacuum cups 62 and 63 in unison tolift the lower glass sheet 12 from the cross conveyor 40 when raised.The upper vacuum cups 90 are adjustably fixed to apertured plate 91which is actuated by the piston in piston cylinder 98 to move the uppervacuum cups 90 vertically in unison with the apertured plate 91. Theparallel vertical axes of the piston cylinders 50 and 98 and thevertical guide rods 47 and 99 insure that the sets of vacuum cups moveonly in vertical directions within the vertically extending space of theassembly station 42. This insures maintaining alignment of the upperbent glass sheet 11 with the lower bent glass sheet 12 even whenseparated. Such alignment maintenance facilitates replacing the upperbent glass sheet in alignment with the lower bent glass sheet when thesandwich is assembled.

The automatic assembly of sandwiches of a pair of bent glass sheets anda sheet of interlayer material depends on the coordination of operationof various actuating mechanisms of the illustrative embodiment includingthe cross conveyor 40, the piston in piston cylinder 98, the applicationof vacuum or pressurized air to the vacuum cups 90, 62 and 63 and vacuummold 131, the piston rod 49, the piston rods 75 and 84, the piston rods104, the piston from piston cylinder 122 and the operation of the rack130 to rotate the pinion 129 and the vacuum mold 131. A typical cyclewill now be described.

The timing sequence of the various actuating mechanisms can becontrolled by any well known timer control circuit or each actuatingmechanism can actuate a limit switch to control the timing of theactuation of a succeeding actuating mechanism in the system. Eitherarrangement is well known in the art of controlling an operating cyclefor different elements in timed sequence and is suitable to operate theapparatus just described.

At the beginning of an assembly cycle, the vacuum mold 131 is orientedinto a convex elevational configuration and is located at the vacuummold loading station 43 to one side of the cross conveyor 40 as thecarriage 120 is retracted to that station. In this position, an operatoris able to mount a sheet 14 of flexible interlayer material inunwrinkled condition onto the upwardly facing surface of convexelevation of the vacuum mold 131. Vacuum is applied at this time to thevacuum mold to hold the flexible sheet of interlayer materialthereagainst in the orientation at which it is applied. While notabsolutely necessary, it is convenient to use sheets of interlayermaterial of slightly larger outline than the outlines of the bent glasssheets 11 and 12 to assure complete alignment between the flexible sheet14 of interlayer material and the bent glass sheets 11 and 12 to beassembled.

At the start of a cycle, the lower vacuum cups 62 and 63 are supportedin spaced relation to the bottom surface of the lower glass sheet of thepair of bent glass sheets as the latter arrives at the assembly station42 supported on rolls of the cross conveyor 40. The latter rolls stoprotating when the glass sheet pair arrives at the assembly station 42.The pair of bent glass sheets stops in approximately the same positionand orientation it will occupy during the assembly operation. While itis unusual for the bent glass sheets in the pair to become misaligned,the glass sheets may sometimes be misaligned relative to one another intheir transverse dimension. It is less likely but also possible that thebent glass sheet pair stops at a position that is misalignedlongitudinally and/or transversely of the desired position. The bentglass sheet pair may also be misoriented. Side edge alignment rolls 80and 89 and the linear rotating rolls 115 of the end edge alignment meanscorrect these problems in a manner to be described in detail.

The lower middle vacuum cups 63 are biased upwardly to be closer to thebottom surface at the central portion of the lower bent glass sheet 12than the end lower vacuum cups 62 are spaced from the end portions ofthe bottom surface that they face. Since all the lower vacuum cups 62and 63 move in unison with table 46, the middle lower vacuum cups 63engage areas in the central portion of the lower glass sheet 12 beforethe end lower vacuum cups 62 engage its end portions so as to flex thelower glass sheet 12 upward in its central portion. At the beginning ofthe cycle, neither vacuum nor pressurized air is applied to any of thelower vacuum cups 62 and 63 or the upper vacuum cups 90.

As the pair of bent glass sheets enters the assembly station 42, thebottom side edge alignment rolls 80 and the top side edge alignmentrolls 89 are retracted from engaging the longitudinal side edges of thebent glass sheets that eventually form the bottom and top side edges ofthe bent laminated windshield that is fabricated. Also, the linearrotating rolls 115 of the end edge alignment means are retracted fromone another to be spaced apart farther than the chord length of the bentglass sheets of the pair. Each linear rotating roll 115 of each pair isarranged relative to the other roll 115 at the end along a plane that isparallel to the line defined by the points along the end edge of thebent glass sheets that usually extend obliquely of the length of theglass sheets (forming the so-called A-post line). This is accomplishedby pivoting each arcuately slotted plate member 106 about pivot pin 110which forms the common pivot axis for each pair of linear rotating rolls115 to orient and lock arcuately slotted plate member 106 at a desiredorientation relative to bearing support member 107 to conform the commontangent lines between linear rotating rolls 115 to the orientation ofthe A-post lines. The linear rotating rolls 115 rotate freely aboutobliquely extending axes that are approximately parallel to the end edgeportions of the bent glass sheet pair.

When the pair of bent glass sheets arrives at the assembly station 42,the top and bottom side edge alignment rolls 89 and 80, respectively,are in their laterally separated positions. Piston 98 extends to lowerthe upper set of vacuum cups 90 into a lowered position a slightdistance above the top surface of the upper glass sheet 11 when thelower glass sheet 12 rests on the rolls of cross conveyor 40. At thistime, piston rods 84 and 75 and 104 move inward toward their respectiveglass edge engaging positions in unison to cause side edge alignmentrolls 89 and 80 to move toward the inward positions defined by stopscontrolling transverse extended movement of the piston rods 84 and 75and the linear rotating rolls 115 move toward inward positions definedby stops controlling longitudinal retracted movement of piston rods 104.These glass edge engagement positions are shown in FIGS. 16 and 17.

While the arcuately slotted plate members 106 are shown as extendingparallel to the bearing support members 107 in FIGS. 4 and 11 to supportthe linear rotating rolls 115 along lines normal to the path defined bycross conveyor 40 for aligning glass sheets of rectangularconfiguration, it is understood that the plate members 106 may be fixedin any angular orientation about pivot pins 110 relative to the bearingsupport members 107, such as in FIG. 10, to have the linear rotatingrolls 115 located with their corresponding portions aligned withtransverse lines extending obliquely to intersect spaced engagementpositions along the end edges of the bent glass sheet pair. Thus, theside edge alignment rolls 89 and 80 and the linear rotating rolls 115move into glass edge alignment positions to align and orient the bentglass sheet pair comprising bent sheets of non-rectangular outlinerelative to the vertically extending space intersecting the desiredassembly positions for the sheets 11, 12 and 14. Such engagement ofrolls 80, 89 and 115 with the edge of the bent glass sheet pair orientsand aligns the pair of bent glass sheets properly relative to oneanother and also orients and aligns a reference line through thethickness of the bent glass sheet pair that coincides with acorresponding reference line through the assembly position for theflexible sheet of interlayer material 14 that is defined by completeextension of the rod from piston 122.

The lower vacuum cups 62 and 63 remain retracted at this stage of thecycle as depicted in FIGS. 16 and 17. The lower bent glass sheet 12rests on the rolls of cross conveyor 40 while the upper bent glass sheet11 nests over lower bent glass sheet 11 when the edge alignment rolls115, 80 and 89 orient and align the bent glass sheet pair.

With the pair of bent glass sheets properly aligned and oriented, thelinear rotating rolls 115 are retracted and the table 46 is lifted sothat the central pair of lower vacuum cups 63 first engages the centralportion of the lower glass sheet 12 to bias the central portion slightlyupward and then all the lower vacuum cups 62 and 63 engage the biasedlower glass sheet. The difference in spacing to the bottom surface ofthe glass sheet from the spring loaded central lower vacuum cups 63compared to that of the unloaded end lower vacuum cups 62 is exaggeratedin FIGS. 16 and 17. In the meantime, the apertured plate 91 has beenlowered to a position wherein the upper vacuum cups 90 are near the topsurface of the upper bent glass sheet of the pair. The limit ofextension of the piston from piston cylinder 98 defines the loweredpositions of the apertured plate 91 and the upper vacuum cups 90.

The upward movement of the table 46 continues to a raised position wherethe top surface of the upper bent glass sheet 11 engages the uppervacuum cups 90. The top and bottom side edge alignment rolls 89 and 80rise on the reduced upper portions 88 and 79 of vertical guide rods 87and 78 due to friction against the rising bent glass sheet pair as thetable 46 rises with the lower vacuum cups 62 and 63. The side edgealignment rolls 89 and 80 continue to align the bent glass sheet pairtransversely until such time as the vacuum cups 62, 63 and 90 engage thebent glass sheets 12 and 11, respectively and vacuum is applied to thevacuum cups. In the meantime, the rack 130 has started to move to rotatepinion 129, box-like housing 128, mounting plate 142 and vacuum mold131. The latter maintains its vacuum to hold the flexible interlayersheet thereagainst as it rotates. The linear rotating rolls 115 arefully retracted at this stage of the cycle.

At this stage of the assembly cycle, retraction of the linear rotatingrolls 115 actuates the application of vacuum to the vacuum cups 62, 63and 90 so that both sheets of the bent glass sheet pair are heldsecurely in position by vacuum so that it is no longer necessary to holdthe side edge alignment rolls 89 and 80 against the opposite side edgesof the bent glass sheet pair. Consequently, with vacuum on upper vacuumcups 90 and on lower vacuum cups 62 and 63, piston rod 84 is retractedto retract the bottom side edge alignment rolls 80 and piston rod 75 isretracted to retract the top side edge alignment rolls 89. Withfrictional engagement against the side edges of the glass sheet pairended, rolls 80 drop on vertical guide rods 78 and rolls 89 drop onvertical guide rods 87 to positions in horizontal alignment with butlaterally recessed from the positions that will intersect the bottom andtop side edges of the next bent glass sheet pair to arrive at theassembly station 42.

While it is most convenient for design purposes that the specificembodiment described provides that both pairs of linear rotating rolls115 are longitudinally movable equal distances in unison betweenlongitudinally spaced positions separated by distances greater than thelongitudinal distances between portions of the longitudinal end edgesengaged by corresponding linear rotating rolls of each pair andpositions engaging said glass end edge portions simultaneously, it isunderstood that longitudinal alignment can be obtained by moving saidpairs of linear rotating rolls different distances longitudinally toengage or disengage the adjacent end edge of the bent glass sheet pair.Similarly, while both pairs of side edge alignment rolls 80 and 89 aremore conveniently designed to be transversely movable in unison forequal distances between transversely spaced positions of disengagementseparated by distances greater than the width of the widest of a familyof glass sheet patterns to be assembled measured between correspondingpositions of the opposite side edges engaged by said side edge alignmentrolls and side edge engaging positions approximately equal to thetransverse distance between said corresponding portions, it isunderstood that it is also permissible to move the pairs of side edgeengaging rolls 80 or 89 different transverse distances in a transversedirection to obtain appropriate transverse alignment. However, the bentglass sheets must be engaged simultaneously by both pairs of linearrotating rolls 115 and both pairs of side edge alignment rolls 80 and 89before the vacuum cups 62, 63 and 90 engage the facing surfaces of thebent glass sheets of the pair. Only the linear rotating rolls 115 aredisengaged from the glass sheet end edges and the side edge alignmentrolls 80 and 89 remain engaged when the lower vacuum cups engage thebent glass sheet pair prior to moving the pair off the support providedby the cross conveyor 40.

Vacuum continues via the upper vacuum cups 90 as well as the lowervacuum cups 62 and 63 while the rack 130 continues to move to rotate thebox-like housing 128, the mounting plate 142 and its connected vacuummold 131 in a counter-clockwise direction toward an orientation ofconcave elevational configuration in which the shaped vacuum mold 131continues to support the flexible sheet of interlayer materialthereagainst by continued application of vacuum. Now, the apparatus isready to separate the upper and lower glass sheets from one another.

At this time, the piston in piston cylinder 98 is ready to begin toraise the apertured plate 91 in response to outward movement of theangled supports 114, to form a gap between the upper and lower bentglass sheets in the vertically extending space at the assembly station42. Simultaneously, the rack 130 has caused the vacuum mold 131 torotate a considerable portion of 180 degrees of rotation.

By the time the next portion of the assembly cycle has occurred, thepiston cylinder 98 has lifted the plate 91 with vacuum continuing on theupper vacuum cups 90 and the lower vacuum cups 63 and 62 support thelower glass sheet in position above the cross conveyor 40 and continueto apply vacuum to the lower glass sheet. The lifting of the upper glasssheet by the lifting of the plate 91 and the maintenance of vacuumthrough the vacuum cups 90 causes a widening gap to develop. In themeantime, the rack 130 has moved to complete the pivoting of the vacuummold 131 into a rotational position where its elevational configurationis now of the same concave elevation as the concave elevationalconfiguration of the bent glass sheet pair.

The piston rod 49 maintains the table 46 in the fixed intermediateposition. When the rack has completed its movement to pivot the vacuummold 180 degrees and the piston of piston cylinder 98 has moved theplate 91 upwardly to its upward position, the rod from piston 122becomes free to extend. Actuation of the piston of piston cylinder 122moves the vacuum mold 131 into the gap between the upper and lower bentglass sheets and into vertical alignment over the lower bent, alignedglass sheet 12 in the vertically extending space that intersects theassembly position at the assembly station 42. During the time that thevacuum mold 131 is moving into the gap, its pivoting has been completed.

The actuation of the piston 122 continues until the vacuum mold 131supporting the unwrinkled flexible sheet 14 of interlayer material byvacuum on its under surface is aligned between the upper glass sheetsupported by vacuum by the upper vacuum cups 90 and the lower glasssheet supported by vacuum by the lower vacuum cups 62 and 63.

While the specific embodiment of this invention maintains the upper bentglass sheet in vertical alignment with the lower bent glass sheet whenthe bent glass sheets are separated for the introduction of the sheet offlexible interlayer material into a position of alignment over the lowerbent glass sheet, and it is most convenient to design the assemblystation in this manner, the position of separation for the upper bentglass sheet can be any position that provides sufficient gap to insertthe sheet of flexible interlayer material and its supporting vacuum moldinto a position of alignment with said lower bent glass sheet totransfer said sheet of flexible interlayer material from said vacuummold to said lower bent glass sheet to form a bent subassembly as longas the apparatus is capable of returning the upper bent glass sheet to aposition of alignment with said lower bent glass sheet after the sheetof flexible interlayer material is deposited thereon.

As stated previously, the springs 66 bias the lower central vacuum cups63 slightly above the mean datum plane of the curvature of the lowerbent glass sheet 12 to bias the lower glass sheet slightly upward in itscentral portion. The interlayer sheet 14, supported on the vacuum mold131, arrives at the vertically extending space in slightly spacedrelation above the lower glass sheet 12 of the bent glass sheet pair andthe bottom surface of the upper bent glass sheet 11 of the pair. Thestate of the apparatus elements at this moment is depicted in FIGS. 18and 19.

As soon as the vacuum mold 131 arrives at the assembly station 42, thepiston from piston housing 141, which has been recessed throughout theprevious steps of the cycle, is extended to lower the vacuum mold 131while the latter supports the flexible sheet 14 of interlayer materialthereon by vacuum against its lower apertured wall 133 which is nowconcavely curved in elevation. The latter now moves downward to applythe unwrinkled flexible interlayer sheet 14 against the top surface ofthe lower glass sheet 12. The alignment pins 145 insure that the vacuummold 131 remains in alignment with the vertically extending space as itlowers toward the lower glass sheet. The stroke of the piston frompiston housing 141 is closely controlled to insure that the sheet offlexible interlayer material engages the top surface of the lower bentglass sheet 12 but is not so long as to develop a fracturing stress inthe lower bent glass sheet 12.

Because of the spring biasing of the central lower vacuum cups 63against the central portion of the lower bent glass sheet, the flexiblesheet 14 of interlayer material makes initial contact in the centralportion of the lower glass sheet that is supported by the biased vacuumcups 63 and as the vacuum mold 131 continues to lower against the topsurface of the lower glass sheet, the area of contact between theflexible interlayer sheet, still supported by vacuum against the lowerconvexly curved apertured wall 133 of the vacuum mold 131, graduallyincreases toward the longitudinal end edges of the lower glass sheet 12.This causes any fluid, such as air, to be forced out toward the endedges of the glass as the flexible sheet 14 increases its area ofengagement with the top surface of the lower glass sheet 12. Since theglass sheet has considerable residual heat from the bending operation,the interlayer sheet, on making contact with the glass, softens andbecomes tacky as it contacts the glass sheet. This tackiness resistsrelative sliding between the contacted sheets. A subassembly formscomprising an upper sheet of flexible interlayer material and the lowerglass sheet with its concavely curved surface facing upward.

As soon as the interlayer sheet 14 makes complete engagement throughoutthe entire extent of the lower glass sheet, vacuum is discontinued intothe vacuum mold 131 to insure that the interlayer sheet 14 separatesfrom shaped apertured wall 133. To further insure this separation, ablast of pressurized air is applied through the supply nozzle 147 to themold 131 and thence through apertures 134 by a suitable valve switchingfrom a source of vacuum to a source of pressurized air (not shown) in amanner well known in the art. Alternately, a separate source ofpressurized fluid may be connected to the mold 131 for initiationsimultaneously with or shortly after the vacuum is discontinued.

Immediately thereafter and while the mold 131 is still pressurized, thepiston within piston housing 141 is retracted, the alignment pins 145insuring that the vacuum mold 131 moves vertically upward in exactly theopposite direction from the one in which it approached the lower glasssheet 12. Pressure on the mold 131 is discontinued. The apertured plate91 supports the upper vacuum cups 90 with vacuum still applied theretoin the same upward position as before to hold the upper bent glass sheet11 in spaced relation to provide the gap through which the vacuum mold131 entered the vertically extending space defined by the spaced bentglass sheets. As soon as the vacuum mold is separated from the sheet offlexible interlayer material forming part of the subassembly that hasjust been formed, the vacuum mold 131 supported from carriage 120 isready to return to its original position.

The clevis 123 attached to the piston rod extending from the pistoncylinder 122 actuates movement of the carriage 120, carrying with it thevacuum mold 131 denuded of the interlayer sheet 14. As soon as thevacuum mold is clear of the vertically extending space within theassembly station 42, the piston extending from piston cylinder 98 isactuated to begin to move downward to lower the upper glass sheet 11toward the subassembly 12, 14. Also, as soon as the vacuum mold 131clears the assembly station 42, rack 130 is actuated to cause pinion 129to rotate in a clockwise direction to begin to return the vacuum mold131 to its initial orientation of convex elevation. At this portion ofthe cycle of operation, subatmospheric pressures are still applied tothe vacuum cups 62, 63 and 90 to maintain the glass sheets in separatedvertical alignment with one another within said vertically extendingspace at this stage of the assembly cycle.

With the gap now cleared of the vacuum mold 131, the apertured plate 91is lowered, thereby lowering the upper bent glass sheet 11 into contactwith the upper surface of the interlayer sheet 14 that forms the uppersurface of the subassembly of interlayer sheet 14 tacked to the lowerbent glass sheet 12. Since the central lower vacuum cups 63 are stillspring loaded, and the upper glass sheet 11 has its normal shape, itmakes initial contact with the central portion of the flexibleinterlayer sheet 14 while still hot enough to make the upper surface ofinterlayer sheet 14 tacky on engagement therewith. As with the lowerbent glass sheet 12, the upper bent glass sheet 11 gradually increasesthe area of engagement with the flexible interlayer sheet 14 in thelongitudinally outward directions from the central portion. Thisarrangement forces any air or other fluids that would otherwise beentrapped between the top surface of the flexible interlayer sheet 14and the bottom surface of the upper glass sheet 11 to be forced outbeyond the margin of the sandwich that results. This situation isdepicted in FIG. 20.

At the same time, rack 130 continues to move causing pinion gear 129 torotate. As a result, the vacuum mold 131 also rotates further toward itsinitial orientation of convex elevation as shown in FIG. 21.

Once the sandwich of two glass sheets and the plastic interlayer hasbeen assembled, the vacuum is discontinued on the vacuum cups, and fluidpressure applied thereto to help separate the vacuum cups from theadjacent bent glass sheet surfaces of the assembly. At this time, withno vacuum applied, the piston rod 49 is lowered to lower the table 46and the lower vacuum cups 62 and 63 and the piston in cylinder 98 israised to lift the apertured plate 91 and its supported upper set ofvacuum cups 90. When the sandwich lowers to the upper level of the rollsof the cross conveyor 40, the sandwich is supported on the rolls of thecross conveyor 40 without changing its orientation or alignment relativethereto.

The apertured plate 91 and its supported upper vacuum cups 90 are in theupward retracted position to provide clearance for the sandwich to leavethe assembly station 42. The table 46 is lowered until all the lowervacuum cups 62 and the spring biased vacuum cups 63 are just below thelevel of the cross conveyor 40. Thus, the resulting sandwich is ready tomove in proper alignment along the cross conveyor 40 from the assemblystation 42 toward the roll pressing apparatus 44. The assembly station42 will then be clear for another bent glass sheet pair to arrive for anassembly treatment similar to the one just described.

While the sandwich and the various structural elements of the assemblystation assume the latter positions, the rack 130 has completed itsreturn movement so that the vacuum mold 131 has resumed its originalorientation of convex elevational configuration. Applying the vacuumagain to the vacuum mold 131 after loading another interlayer sheet 14on the convexly oriented apertured wall 133 permits an operator tosupport the flexible interlayer sheet against the vacuum mold 131 inunwrinkled condition so that the interlayer sheet is now ready forassembly between the next bent glass sheet pair that arrives at theassembly station.

Two benefits are derived from the present inventions. One is the savingof energy that results from using the residual heat in the glass sheetsto make the interlayer sheet tacky during assembly. Manual handling ofthe glass sheets is eliminated entirely so that it is unnecessary tocool the bent glass sheets sufficiently to enable operators to handlethe glass without undue harm. The other benefit is that automaticassembly apparatus makes it possible to assemble the bent glass sheetsin exact alignment with the flexible interlayer sheet, and to have eachsuccessive sandwich produced in response to exactly the same sequence ofmovements of alignment means, vacuum cups and vacuum mold to insure moreprecise alignment from sandwich to sandwich than is possible from amanual assembly operation.

While the temperatures described herein may vary from pattern topattern, depending upon the severity of bend imparted to the bent glasssheet pair, in a typical operation, a typical temperature range for theglass sheet pair on entering the assembly station is on the order of275° to 302° F. (135° to 150° C.) so that the temperature of the topglass sheet 11 is no colder than about 200° F. (93° C.), preferably atleast 248° F. (120° C.), when it engages the upper surface of theinterlayer sheet 14 during the assembly operation. Of course, thetemperature of the lower bent glass sheet 12 when it engages theflexible interlayer sheet is no colder than the plastic engagingtemperature of the upper bent glass sheet so that the flexibleinterlayer sheet becomes tacky on both surfaces due to its engagementwith the relatively hot glass sheets. This tackiness is sufficient toprevent sliding of the interlayer sheet relative to the opposite glasssheets on engagement therewith.

The temperature of the sandwich at the end of the assembly processshould be sufficiently high to permit the sandwich to be conveyedthrough at least one pair of prepressing rolls and then be edge sealedat a minimum temperature of approximately 200° F. (93° C.). While it maybe possible to reheat the edge of the sandwich after prepressing tofacilitate edge sealing, it is preferred to avoid the need for suchreheating. Cooling experiments conducted at a temperature of 74° F. (24°C.) using pairs of bent glass sheets, each sheet having a nominalthickness of 90 mils (2.3 millimeters) disclosed an average cooling timeof 4 minutes 44 seconds for a pair of sheets to cool from 300° F. (149°C.) to 200° F. (93° C.) when the sheets were nested and an averagecooling time of 2 minutes 19 seconds for single bent sheets of suchthickness. Pairs of nested bent glass sheets of this nominal thicknesscooled from 275° F. (135° C.) to 200° F. (93° C.) in 3 minutes 40seconds and single bent glass sheets cooled in an average cooling timeof 1 minute 49 seconds. These averages were based on 5 readings perexperiment (nested sheets versus single sheets) at each temperaturerange. The assembly apparatus described herein completed the assemblyprocess in 35 seconds from the moment of arrival. While several minutesare available for prepressing and sealing the edge of a bent glass sheetsandwich assembled at the assembly station, it is prudent to completethe prepressing step as soon as possible after completing the assemblyoperation.

Many factors contribute to obtaining acceptable sandwiches of bent glasssheets and a flexible interlayer sheet. The side edge alignment rolls 80and 89 and the linear end edge alignment rolls 115 of the invention ofJames L. Valimont and Barry L.Shadle for aligning bent glass sheetscovered in copending U.S. patent application Ser. No. 287,608 aremounted on generally vertically oriented guide rolls and rise with thebent glass sheet pair to maintain alignment of the bent glass sheet pairuntil the vacuum cups engage the bent upper and lower glass sheets byvacuum. The linear rotating rolls 115 which comprise the end edgealignment means provide end edge engagement for shaped glass sheets bymoving longitudinally to facilitate longitudinal alignment of the bentglass sheet pair relative to the assembly station. The pivotal mountingadjustment of the end edge engaging rolls in pairs about common axesenables the pairs to move in unison to align and orient each end edge ofthe bent glass sheets regardless of whether they extend obliquely ornormal to the length of the sheets. The use of a set of upper vacuumcups to engage the top surface of the upper glass sheet and a set oflower vacuum cups to engage the bottom surface of the lower glass sheetafter the bent glass sheet pair are oriented and aligned by the edgeengaging rolls maintains the bent glass sheets in vertical alignmentwith the vertically extending space containing the alignment positionand permits the separation of the bent glass sheets from one another inexact alignment during the insertion of the flexible interlayer sheetsupported by the vacuum mold and released from vacuum support to depositthe flexible interlayer sheet in proper alignment and orientation on thelower bent glass sheet to form a subassembly which becomes a sandwichwhen the upper bent glass sheet is mounted over the flexible interlayersheet of the subassembly.

The use of a shaped rotatable vacuum mold of the present inventionhaving curved walls conforming in shape to that of the bent glass sheetswith means to move said vacuum mold from a convex elevationalconfiguration at the mold loading station to a concave elevationalconfiguration at the assembly station enables an operator to load aflexible interlayer sheet on the mold at said mold loading station inpositions to locate the bent glass sheet pair to receive said pivotedflexible interlayer sheet onto a shaped glass sheet of concave elevationat said assembly station in proper orientation and alignment withoutwrinkling the flexible interlayer sheet.

The use of spring biased vacuum cups facing the central portion of thelower glass sheet as taught in the Valimont and Kelly invention coveredin copending U.S. patent application Ser. No. 287,600 provides an upwardbias that temporarily distorts the lower bent glass sheet upwardly whenthe flexible interlayer sheet is applied thereto and temporarilydistorts the subassembly when the upper bent glass sheet is loweredthereagainst. These temporary distortions help remove entrapped air andother fluids from the interfacial surfaces of adjacent sheets of thesandwich.

The various features all assist in making possible the automaticassembly of a bent glass-plastic sandwich from a pair of bent glasssheets that separates the bent glass sheets, applies the flexibleinterlayer sheet against one of the bent glass sheets to form asubassembly and applies the other bent glass sheet to the exposedsurface of the interlayer sheet before the residual heat in the glasssheets that developed during their bending is dissipated to the extentthat the glass sheet become too cold on engaging the interlayer sheet tomake the interlayer sheet tacky. Providing assembly apparatus thatcompletes the transfer and assembly in 35 seconds or less insures thisdesired result.

While the specific embodiment described relates to assembling a sandwichcomprising a pair of bent glass sheets of conforming configuration witha sheet of flexible interlayer material therebetween, and a subassemblyof a single bent glass sheet and a sheet of flexible interlayer materialis assembled during the assembly of said sandwich, it is understood thatthe present invention also comprehends that the subassembly may be theresulting product desired. Such a subassembly may be fabricated into abilayer windshield, particularly when the flexible interlayer materialis composed of polyurethane.

It is also within the gist of this invention to orient the bent glasssheet pair and the vacuum mold to have their longitudinal dimensionsextend transverse to the path defined by the cross conveyor. It is alsowithin the gist of this invention to have the conveyor that connects thebending mold unloading station at the bending lehr exit with theassembly station to extend as a longitudinal continuation of theconveyor through the bending lehr instead of extending transversely ofthe bending lehr conveyor as in the illustrative embodiment.

The illustrative embodiment also includes a device to transfer a vacuummold from a vacuum mold loading station to the assembly station. It isalso convenient for loading the vacuum mold with a flexible sheet ofinterlayer material to orient the mold to have a convex elevationalconfiguration to facilitate loading a flexible sheet of interlayermaterial in unwrinkled condition thereon and to pivot the mold into aconcave elevational configuration conforming to that at which the bentglass sheets are supported for assembly. While it is more convenient andsimpler to pivot the vacuum mold about a single axis as depicted in theillustrative embodiment, it is also within the gist of this developmentto orient the vacuum mold about a vertical axis as well as a horizontalaxis to bring the vacuum mold into alignment with one or more bent glasssheets supported with their length extending transverse to the conveyorpath, instead of longitudinally of the path as in the illustrativeembodiment.

The illustrative embodiment of assembly apparatus described herein iscapable of aligning and assembling a family of windshield patternshaving a range of sizes (lengths and widths), various outlines includingobliquely extending end edges at a range of oblique angles withincertain limits, various depths of bend and various angles of bendwherein the tangent at the longitudinal end of the sandwich assembledmakes an angle with the tangent to the main portion of the sandwich thatvaries within certain limits. The illustrative embodiment is alsocapable of aligning and assembling sandwiches having asymmetrical shapeswith respect to either their longitudinal axis, their transverse axis orboth of these axes.

The form of the invention shown and described in this disclosurerepresents an illustrative preferred embodiment of apparatus containingthe present invention and several variations thereof. It is alsounderstood that various changes may be made without departing from thegist of the invention as defined in the claimed subject matter whichfollows. For example, the specific preferred embodiment describes anassembly operation in which bent glass sheets are oriented in anessentially horizontal orientation to have a concave elevationalconfiguration during assembly of the sandwich. It is apparent thatoblique and vertical orientations may be maintained by edge alignmentmeans cooperating with opposed sets of vacuum cups used in cooperationwith a shaped vacuum mold having an elevational configuration conformingto those of the conforming glass sheets with means to move the mold froma mold loading station to an assembly station where the mold assumes theorientation of support for the bent glass sheets. It is also understoodthat the combination of method steps described may be modified withoutdeparting from the gist of the invention defined therein as follows.

What is claimed is:
 1. In the method of assembling a sheet of flexibleinterlayer material against a hot sheet of bent glass while the latteris at a temperature at which the flexible interlayer sheet becomes tackyon contact with said hot glass sheet, the steps of holding a sheet offlexible interlayer material preparatory to assembling said sheetagainst a bent glass sheet oriented to have a concave elevationalconfiguration comprising supporting said sheet of flexible interlayermaterial on a vacuum mold having a first wall whose shape conforms tosaid configuration while said mold is oriented so that said first wallhas a convex configuration in elevation, drawing vacuum through saidfirst wall to support said sheet of flexible interlayer materialthereagainst, changing the orientation of said vacuum mold to change theorientation of said first wall so that the latter has a concaveelevational configuration while continuing to draw vacuum through saidfirst wall to maintain said sheet of flexible interlayer materialthereagainst in a shape conforming to said configuration, and movingsaid vacuum mold into alignment with said bent glass sheet whilesupporting said sheet of flexible interlayer material thereagainstpreparatory to transfer said flexible sheet from said first wall of saidvacuum mold to said hot bent glass sheet.
 2. A method as in claim 1 foruse preparatory to assembling said sheet of flexible interlayer materialbetween a pair of aligned bent glass sheets of conforming shape, furtherincluding supporting said pair of aligned bent glass sheets in nestingrelation to one another in said concave elevational configuration tohave said pair include an upper bent glass sheet and a lower bent glasssheet, further including separating said bent glass sheets from oneanother to form a gap between said bent glass sheets prior to movingsaid vacuum mold into alignment with said lower bent glass sheet whilesupporting said flexible sheet of interlayer material thereagainst andengaging said lower bent glass sheet with said sheet of flexibleinterlayer material to tack said flexible sheet of interlayer materialagainst said lower bent glass sheet to form a subassembly.
 3. The methodas in claim 1, further including removing said vacuum mold from the gapbetween said upper glass sheet and said subassembly, and bringing theupper bent glass sheet into engagement with said sheet of flexibleinterlayer material to tack the latter against said upper bent glasssheet and convert said subassembly to a sandwich.
 4. In the method ofassembling a sheet of flexible interlayer material against a sheet ofbent glass, the steps of holding a sheet of flexible interlayer materialpreparatory to assembling said sheet against a bent glass sheet orientedto have a concave elevational configuration comprising supporting saidsheet of flexible interlayer material on a vacuum mold having a firstwall whose shape conforms to said configuration while said mold isoriented so that said first wall has a convex configuration inelevation, drawing vacuum through said first wall to support said sheetof flexible interlayer material thereagainst, changing the orientationof said vacuum mold to change the orientation of said first wall so thatthe latter has a concave elevational configuration while continuing todraw vacuum through said first wall to maintain said sheet of flexibleinterlayer material thereagainst in a shape conforming to saidconfiguration, and moving said vacuum mold into alignment with said bentglass sheet while supporting said sheet of flexible interlayer materialthereagainst preparatory to transfer said flexible sheet from said firstwall of said vacuum mold to said bent glass sheet.
 5. A method as inclaim 4 for use preparatory to assembling said sheet of flexibleinterlayer material between a pair of aligned bent glass sheets ofconforming shape, further including supporting said pair of aligned bentglass sheets in nesting relation to one another in said concaveelevational configuration to have said pair include an upper bent glasssheet and a lower bent glass sheet, further including separating saidbent glass sheets from one another to form a gap between said bent glasssheets prior to moving said vacuum mold into alignment with said lowerbent glass sheet while supporting said flexible sheet of interlayermaterial thereagainst and engaging said lower bent glass sheet with saidsheet of flexible interlayer material to mount said flexible sheet ofinterlayer material against said lower bent glass sheet to form asubassembly.
 6. The method as in claim 5, further including removingsaid vacuum mold from the gas between said upper glass sheet and saidsubassembly, and bringing the upper bent glass sheet into engagementwith said sheet of flexible interlayer material to mount said upper bentglass sheet against said sheet of flexible interlayer material andconvert said subassembly to a sandwich.